Artificial hand and abm



Il i ITED STATES PATENT OFFICE.

JOHN S. DRAKE, OF BOSTON, MASSACHUSETTS.

ARTIFICIAL HAND AND ARM.

Specification of Letters Patent No. 15,372, dated July 22, 1856.

To all whom fit may concern.'

Be it known thatI, JOHN S. DRAKE, of the city of Boston, in the countyof Suffolk and State of Massachusetts, have invented, made, and appliedto use certain new and useful Improvements in Artificial Hands and Arms;and I do hereby declare that the following is a full, clear, and exactdescription of the construction and operation of the same, referencebeing had to the annexed drawing, making part of this specification,wherein- Figure 1, is a view of the hand and arm with its exteriorcovering removed to show the skeleton or metallic parts. Fig. 2, is asection through the hand, wrist, and one of the fingers, and Fig. 3, isa cross section at the wrist.

Similar marks of reference denote the same parts'.

Artificial hands and arms have heretofore been constructed to set ontothe stump of the lower or upper joint of the arm, and have been providedwith springs and other attachments for causing the lingers and hand tograsp any substance placed within, but these are unhandy in use and donot accomplish near all t-he purposes required of a hand.

The nature of my invention consists in a peculiar construction of elbowwhereby the position of the fore arm and stump can'be varied, also in anopen circular wrist which allows the hand to be turned to about theextent of a natural one; and t-he fingers and thumbs are so constructedand arranged in connection with parts in the hand, that by pulling outasmall button or stop near the wrist, the hand is partially shut and thefingers and thumb can then be pressed down onto and retain any articlethat may be placed in the hand; or by simply forcing in the buttonaforesaid the fingers and thumb are liberated and can be distended inthe natural form.

a is a socket to be formed of sole leather or suitable material, intothe shape of the stump or arm to which the same is to be applied; thisis to be padded and provided with straps as usual for attaching the sameinto place. b, are straps from said stump to the elbow joint 1.

2, is a curved guard against which the metallic straps c, of the forearm IIlOVe and abut against straps b, when the arm is fully distended.

3, is a ratchet wheel on the part c, at the joint 1, with a pawl 4 andspring 5, which will hold the fore arm at any desired angle relativelywith the stump and when the said fore arm is to be dropped so as to hangdown the back of the pawl 1,4 is pressed on, disengaging it from theratchet 3.

0l, d, are whalebone frames or ribs extending from the straps c, to thestraps e, of the wrist which wrist (6,) is formed circularly andreceives within it the wrist piece f, that has mortises 7, 7, runningpart of the way around on opposite sides, and receiving rivets 6, insaid mortises connecting said piece f to the straps e, and allowing saidwrist to be turned a limited amount around the line of aXis of the forearm the extent of motion is determined by a rivet or stop.

9, 9, are joints on the wrist piece f connecting the piece g forming thepalm of the hand, and the extent of motion is limited at the oints 9 bya rivet or stop at e, taking a shoulder on the joint as seen by dottedlines` in Fig. 2, and by the edge of the wrist piece f as at e2.

7L, is the back piece of the hand, ointed at 10, and connected by a boltat 11, thereby allowing access to the working parts of the hand.

z', z', z', z', are the knuckle joints connecting the iirst joints 12 ofthe fingers; 7c, second joints of ngers and Z, are the third joints.

13, is a ratchet at he base of the third joint which may be used on onlythe fore or middle fingers or may be applied to all the fingers andthumb; and to this ratchet a pawl m is applied, the same being hung inthe middle at 14, so that the one end can be pressed into and hold theratchet and third joint of the finger in the desired po- V sition, or bedisengaged therefrom on pressing in the other end; both these operationsbeing performed by pressing on the outside covering of the hand by theother hand of the user.

n, is a pawl on a center 28, between sides 12, kept to a ratchet wheel15 on the end of the second joint c, by a spring 16, and 17 is a ratchetwheel on the joint z', taking a pawl 0, on the inner side of the plateg, and 18, is a spring to keep said pawl to the ratchet.

It will now be seen that each finger being thus constructed, one or allof them can be turned over toward the palm of the hand and pressed ontoany article therein so as to hold the same firmly in consequence of theratchets and pawls aforesaid, the manner therefore in which I disengagethese pawls and straighten out the fingers when desired is as follows.

79 is a cross bar sliding at its ends in slots in the edges of the hand(g) and from this a bar g passes to a bent crank 9n on the center pin ofthe joints z' and s is a rod and button through a slot in the wristwhich is acted upon by the other hand of the wearer of this arm, and ifpulled out from the wrist forces up the cross bar 79 or vice versa.

t t t are rods ointed at 19 to the knuckles and passing freely throughthe rod 79 and provided at this end with a head or bend to preventpulling out of said bar 79.

Ifnow the button s be pulled out-the cross bar 79 is driven up andoverruns the wires or rods t, allowing them afterward to draw throughasany one or more of the fingers may be turned down, and at this pointthe bar 79 stands opposite a depression in each of the pawls 0, so thatthey act freely in holding the fingers; but if the buttons be pressedin, the bar 79 is drawn down and taking the ends of the aawls odisengages them from the ratchets 1 allowing the rods t to pull thefingers back into a dist-ended position, and as the first joints (12)become extended the cam heads 20 on the rods t taking the ends of thepawls m disengage the same from the ratchets 15 and allow the secondjoints 70 to be distended.

The thumb (o) is formed similarly to one of the fingers, and is attachedby a rivet at 24 to the hand g so that it can have a little swayingmotion (see dotted arc, Fig. 2). rIhe second joint fw is provided with aratchet similar to the ratchet 15, and the third joint m has a ratchet(similar to 18) taking a pawl 26 the same as the pawl m; j

u is a bar or pawl kept to the ratchet on the end of the joint w by thespring 25, the same as the pawl u, and in order to disengage this pawl uwhen thebar 79 is drawn down I make use of a pin 21 on the bar Q (seealso dotted lines, F ig. 1), acting on a lever 22, on the other end ofwhich is an eye 23 taking loosely the end of the bar u, so that said endis carried toward the knuckles as the button s is forced in and theupper end of said bar u, which forms a pawl is disengaged from itsratchet.

The covering which I make use of is to be composed of leather and indiarubber, or of any suitable material, elastic at the elbow joint and at'all other parts where required, and the hand should ibe of a separatepiece from the covering of the arm so as to allow motion for the wrist;I propose that the said covering be formed in a peculiar manner ofground leather and india rubber, but as' this becomes a separateinvention the same may be the subject of another patent, sufiice to saythat the general outlines of the covering are indicated by dotted lines,Fig. 1.

e is a spring hook or clasp which may be attached to the palm of the`hand near the wrist beneath which to slip a knife, fork or other toolin general use by the wearer.

1What I claim and desire to secure by Letters Patent is v 1. The ratchetS'and pawl 4 in the elbow joint to sustain the forearm at the properposition relatively with the stump substantially as specied. Y

2. I also claim the construction of the wrist joint (f) with the slotsand stops foi allowing the necessary motio'n substantially as specified.

3. I also claim forming the knuckle joints and joints between thediiferent parts of the lingers and thumb with ratchets and pawls so asto secure said joints at the point to which they may be moved inadjusting the fingers or thumb to any given article or purposesubstantially as specified.

et. I also claim disengaging the pawls u and o from their respectiveratchets by means of the sliding cross bar 79 (actuated by competentpower) rods t and cam pieces 20 substantially as specified.

5. And I also claim the arrangement of the bars 79 and g, crank 9',button and rod s for actuating the bar 79 and rods t substantially asspecified, and in connection with this arrangement I also claim thecross lever 22 for actuating the bar and pawl u of the thumbsubstantially as specified.

In witness whereof I have hereunto set my signature this nineteenth dayof June, 1856.

JOHN S. DRAKE. Witnesses:

F. E. A. WoLooTr, W. I-I. L. SMITH.

